Within the presented paper, different approaches to determine kinetic reaction models governing pyrolysis of three waste biomass types: waste wood (WW), waste straw (WS) and sewage sludge (SS) based on 5 dynamic heating runs (5, 10, 20, 30, 40 K/min) at TGA are presented and discussed. Fuel properties with lignocelluloses content of the investigated feedstock are presented and discussed. Ambiguous results of the generalized master-plot method draw the idea of determining actual reaction models using the isoconversional methodology. Friedman method provided apparent activation energies as a root for further calculations being the 48.1-294.3 kJ/mol for WS, 21.0-361.9 kJ/mol for WW and 58.1-484.3 kJ/mol for SS. Isoconversional pre-exponential factors were determined using linear compensation effect and were 7.2.10(6)-1.8.10(21) 1/min, 1.6.10(4)-1.2.10(25) 1/min, and 1.5.10(9)-3.2.10(30) 1/min for WS, WW, and SS respectively. Based on isoconversional parameters, actual profiles of reaction models were estimated using the t-Students distribution for 95% confidence intervals and verified in the modelling of pyrolysis conversion profiles. Isoconversional pyrolysis models resulted in fitting to experimental profiles with non-linear coefficients of determination equal to 0.9912, 0.9876, and 0.9406 for WW, WS, and SS respectively. (C) 2020 The Authors. Published by Elsevier Ltd.